The present invention relates, in general, to insulated steam injecting tubing and, in particular, to a new and useful device for sealing a port that communicates with an annular space between inner and outer tubines of the insulated steam injecting tubing, to maintain a vacuum in that space which was drawn through the port.
U.S. Pat. No. 4,396,211 to McStravick et al discloses an insulated tubular conduit for use in forming a tubing string in a subterranean well. The conduit comprises inner and outer tubing with an annular cavity formed therebetween. A fixture is provided for evacuating the gases from the annular cavity. This fixture includes a clamp extending around the exterior of the outer tubing. A passage extends radially through the fixture and communicates with an evacuation port in the outer tubing. A plug, such as a tapered pin, surrounded by an annular seal, can be inserted into this passage. A vacuum hose connected to the fixture and communicating with the passage can be connected to a vacuum pump for drawing a vacuum from the annular cavity. After a suitable vacuum has been drawn, the pin which is a tapered pin, is driven into the vacuum part to close the annular cavity.
U.S. Pat. No. 1,472,019 to Hitch discloses a double walled receptacle in the form of a bottle having an outer shell and an inner shell wherein an air chamber is provided between the inner and outer shells. A tapered air passage is formed in the outer shell. A sleeve is clamped to the receptacle and provides a passageway and communication with the tapered air passage which, in turn, provides a passage for drawing air from the air chamber. A driver bar fits within the sleeve passageway and a tapered plug is supported on the end of the driver bar. After an appropriate vacuum has been created in the chamber, the driver bar is struck with a tool to drive the plug into the tapered air passage to seal the chamber. A similar device for sealing off a metal tank is disclosed in U.S. Pat. No. 2,032,862 to Wilkins. In this patent, a ram is used to force a sealing plug into a chamfered and slightly tapered opening in a tank. An end of the ram carries a spring wire holder and over this holder, there is forced a plug. The plug is drilled at the surface which contacts the ram. The hole is of a size sufficiently small to permit the plug to be pressed tightly over the holder and to be securely attached thereto.
None of the patents discussed above discloses the provision of a breakable tab portion between a plug portion and a shank portion of a pin which is driven into an aperture of an outer tube to seal the annulus between the outer and inner tube. These features, however, are found in the present invention and distinguish it from the older patent.
Other references which are of interest to the present application are as follows:
U.S. Pat. No. 29,582 to Gill
U.S. Pat. No. 30,440 to Wildey
U.S. Pat. No. 311,253 to Mussel
U.S. Pat. No. 1,150,242 to Bartlett
U.S. Pat. No. 1,463,723 to Otsuki
U.S. Pat. No. 1,848,319 to Clifford
U.S. Pat. No. 2,016,045 to Munters
U.S. Pat. No. 2,367,756 to Cummings
U.S. Pat. No. 3,065,583 to Miller
U.S. Pat. No. 3,240,227 to Burkholder
U.S. Pat. No. 3,406,987 to Hunder et al.